Alterations of red blood cell sodium transport during malarial infection

Abstract

A B S T R A C T Previous studies have suggested that malaria induces changes in erythrocytic membrane permeability and susceptibility to osmotic lysis. The present study investigated erythrocytic transport of sodium with cells from Rhesus monkeys infected with Plasmodium knowlesi. Red blood cell sodium concentration was significantly elevated in 37 parasitized animals (21.8 ±1.2 mM; mean +SEM), as compared to 23 control animals (10.0 +0.38 mM). The cellular sodium increased with the density of parasitemia and the cellular potassium decreased in proportion to the elevation of sodium. Nonparasitized as well as parasitized erythrocytes possessed this abnormality of cation metabolism. Effective chloroquine therapy reversed the changes over a period of 4 days.Active sodium outflux rate constants were depressed in animals with malaria (0.202 +0.012), as compared to controls (0.325 ±0.027). Passive sodium influx rate constants were higher in infected monkeys (0.028 +0.002) than in control animals (0.019 +0.002). The cross incubation of malarial plasma with normal red blood cells induced a 22% diminution in active sodium outflux but no changes were observed in sodium influx.It is concluded that malaria alters erythrocytic sodium transport in all erythrocytes. The elevated intracellular sodium concentration is the net result of decreased sodium outflux and increased sodium influx. The plasmodium organism or the affected host may produce a circulating substance that is deleterious to erythrocytic membrane cation transport.

The effects of transport inhibitors on sodium outflux and influx in red blood cells: evidence for exchange diffusion

“…The sodium outflux (efflux) method has been described previously (7) and was essentially the method of Sachs and Welt (8). Basically, this technique measured the rate of appearance of sodium 22 into the extracellular medium from isotopically labeled fresh, human erythrocytes obtained in heparin immediately before the study.…”

“…Basically, this technique measured the rate of appearance of sodium 22 into the extracellular medium from isotopically labeled fresh, human erythrocytes obtained in heparin immediately before the study. The sodium influx technique has also been recently outlined (7,9). This measurement quantitated the amount of sodium 22 which appeared in erythrocytes from an isotopically labeled extracellular medium; all influx measurements were corrected for sodium 22 calculated to have been simultaneously lost due to sodium outflux.…”

Na+/K+ATPase Activity in Sheep with Natural Babesiosis

“…In an early study, Dunn (1969) postulated that increased erythrocyte Na + /K + ratio of monkeys infected with Plasmodium knowlesi is due to the impairment of the Na + /K + ATPase pump activity. Besides, Ginsburg et al (1986) put forward that erythrocytes infected with Plasmodium falciparum gain Na + and lose K + ions because of inhibition of erythrocyte Na + /K + ATPase activity.…”

Natural Plasmodium knowlesi malaria infections in humans

“…Plasmodium knowlesi ha sido estudiado para resolver problemas relacionados con el cultivo de otros parásitos de la malaria (16), para mejorar la comprensión del metabolismo de los plasmodios (17,18) y los mecanismos de acción de los medicamentos y la respuesta a ellos (19,20). Sin embargo, su diagnóstico aún representa un reto, primero, por su similitud morfológica con otras especies de plasmodios mucho más prevalentes en la población humana, como P. malariae (2), y, en segundo lugar, porque no se dispone de pruebas diagnósticas con anticuerpos específicos para su identificación (21).…”